As subscribers and network traffic in Long Term Evolution (LTE) based networks continue to grow, network providers are continually looking for ways to increase spectrum efficiency and user equipment (UE) throughput. One way of doing so is referred to as Downlink coordinated multipoint (CoMP). Downlink CoMP is one of LTE's advanced features that allows for mitigation of inter-cell co-channel interference to improve downlink spectrum efficiency and UE throughput of the LTE network. In particular, downlink CoMP has two main categories, namely, joint processing (JP) and coordinated scheduling and coordinated beamforming (CS/CB) in which joint processing includes joint transmission (JP/JT) and dynamic cell selection (JP/DCS). JP typically involves coordination between multiple nodes, e.g., eNodeBs, by making UE data available to each node in the coordination.
As a result, UE data needs to be delivered over the backhaul network to other coordinated eNodeBs for wireless transmission. For the JP/JT, data transmission is performed simultaneously at multiple nodes, thereby providing improved receive signal quality and strength for targeted UEs due to specially pre-coded data signals that constructively combine and enhance each other while undesired interference destructively cancel each other over the air. For JP/DCS, data transmission is performed by an individually selected eNodeB at a time, thereby providing improved received signal quality at the UE as well due to no interferences generated from neighboring eNodeBs during the transmission. In contrast, CS/CB requires UE data to be available only at the serving eNodeB. It typically involves transmission from a serving eNodeB to its served UE all the time, in which scheduling decisions and beam selection are coordinated in order to avoid interference. Therefore, scheduling and beam selection decisions need to be coordinated among multiple neighboring eNodeBs, which consumes a considerable amount of backhaul resources.
While the standardization of CoMP technology is still ongoing, downlink CoMP is still typically not available for practical use in current LTE networks due to the complexity and difficulty of implementation of the technology such as the backhaul signaling requirements as mentioned above, which is a significant issue. For example, typical downlink CoMP involves a substantial amount of multi-cell cooperative processing that causes backhaul signaling overhead and inter-cell communication to increase dramatically. The cost caused by the increase quickly becomes too large to be affordable from an implementation perspective, particularly when a large number of cells in the LTE network are involved in the cooperative process.